Disposable garments

ABSTRACT

Diapers, incontinence pants or baby training pants with two leg openings that each have an upper end portion and a lower end portion, a crotch portion between the lower end portions, a plurality of elastic members surrounding each leg opening, the plurality of elastic members adjacent the upper end portion of each leg opening exerting less tension or being spaced further apart than the plurality of elastic members adjacent the lower end of each leg opening.

This is a continuation of application Ser. No. 07/738,447, filed Jul.31, 1991 (now U.S. Pat. No. 5,197,960) which in turn is a divisional ofSer. No. 07/626,783, filed Dec. 13, 1990 (now U.S. Pat. No. 5,055,103)and the benefits of 35 USC 120 are claimed relative to these priorapplications.

BACKGROUND OF THE INVENTION

The present invention relates to disposable garments and moreparticularly to garments such as diapers, incontinence pants and babytraining pants.

The garments of such type are usually provided around the respectiveleg-openings with elastic means. In general, the elastic means arebonded, under stretching, to at least one of the topsheet and thebacksheet with adhesive.

With particular garments, for example, a disposable diaper, undesirableleakage of excretions often occurs, regardless of the user's gender, atthe opposite sides of the crotch area defined between the oppositeleg-openings due to location and orientation of the urinary organs.

Accordingly, it is preferred to provide an arrangement such that theelastic means have a higher tensile stress at the lower middle area ofeach leg-opening than at the remaining area and thereby allow the diaperto contact with the wearer's skin at this area with a higher fitness.

In view of the fact that, after put on the user, the diaper can moverelative to the wearer's skin at the upper middle area of eachleg-opening more easily than at said lower middle area, it is preferredalso to decentralize the tensile stress of the elastic means at saidupper middle area, allowing the diaper to contact with the wearer's skinover a relatively large area with a moderate fitness.

However, in the diaper having been proposed and commonly used inpractice, no consideration can be found about gradually varying thetensile stress of the elastic means around the leg-openings anddecentralizing the said tensile stress depending upon the locationaround the leg-openings.

It is a first object of the invention to provide disposable garmentsincluding elastic means surrounding each leg-opening which has a tensilestress gradually decreasing from adjacent the lower middle area towardthe upper middle area of the leg-opening.

It is a second object of the invention to provide disposable garmentsincluding elastic means surrounding each leg-opening with a tensilestress gradually decentralized from adjacent the lower middle areatoward the upper middle area of the leg-opening.

SUMMARY OF THE INVENTION

The first object set forth above is achieved, in accordance with theinvention, by disposable garments having a topsheet, a backsheet andelastic means provided around leg-openings defined at opposite sides ofa crotch area connecting front and rear sections of the top- andbacksheets, wherein the elastic means surrounding each of theleg-openings comprises first and second elastic members, the firstelastic member is positioned substantially along a front half of theleg-opening while the second elastic member is positioned substantiallyalong a rear half of the leg-opening so that the first and secondelastic members intersect each other at their longitudinally inner endslocated adjacent the lower middle of the leg-opening, and the first andsecond elastic members have their tensile stress gradually decreasingfrom the longitudinally inner ends toward their longitudinally outerends.

The second object set forth above is achieved, according to theinvention, by disposable garments as has been described above, whereinthe elastic means surrounding each of the leg-openings comprises aplurality of first elastic members and a plurality of second elasticmembers and the first and second elastic members have their inter-memberspacings gradually enlarged from their longitudinally inner ends towardtheir longitudinally outer ends.

In a preferred embodiment, the first and second elastic memberssurrounding each of the leg-openings are continuous to those surroundingthe opposite leg-opening, respectively, and intermediate lengths of therespective continuous elastic members connecting the oppositeleg-openings extend across the crotch area transversely thereof.

In this manner, the invention allows the garments to contact with thewearer's skin adjacent the lower middle area of each leg-opening under ahigher fitness than at the upper middle area thereof, since the firstand second elastic members have the tensile stress gradually decreasingfrom their longitudinally inner ends toward their longitudinally outerends, i.e., gradually increasing from their longitudinally outer endstoward their longitudinally inner ends.

Furthermore the tensile stress of the first and second elastic membersis transversely decentralized in the proximity of the upper middle areaof each leg-opening, since the first and second elastic members comprisea plurality of members, repsectively, and their inter-member spacingsare gradually enlarged from their longitudinally inner ends toward theirlongitudinally outer ends.

By using such garments of the invention, leakage of excretions readilyoccurring through the lower middle area of each leg-opening, which hasconventionally been remarkable and almost inevitable, can be noweffectively alleviated, since the invention allows the elastic membersto contact with the wearer's skin in the proximity of the lower middlearea of each leg-opening under a relatively firm fitness. In addition,the upper area of each leg-opening most readily movable relative to thewearer's skin can be maintained in contact with the wearer's skin undera relatively weak tensile stress but over a large area, since thetensile stress of the elastic members is decentralized in the vicinityof the upper area of each leg-opening.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing an embodiment of an assembledgarment constructed in accordance with the teaching of the invention;

FIG. 2 is an exploded perspective view of an assembled garment; and

FIG. 3 is a plan view showing by way of example the manner in which theelastic means is arranged in an unassembled garment.

PREFERRED EMBODIMENT OF THE INVENTION

The other features and advantages of the invention will be readilyunderstood from the following description made in reference with theaccompanying drawings.

Referring first to FIG. 1, a diaper of pants type 1 is shown in aperspective view. As shown, the diaper I has leg-openings 2 and awaist-opening 3, both being provided with elastic means 4, 5,respectively.

Referring to FIG. 2, the same diaper I is shown in an explodedunassembled perspective view. As illustrated, the diaper 1 comprises awater-permeable topsheet 6 being stretchable both in length and width, awater-permeable backsheet 7 being also stretchable both in length andwidth, a mat- or sheet-like water-absorbent core 8, and the elasticmeans 4, 5 surrounding the leg-openings 2 and the waist-opening 3,respectively. Front and rear sections 10, 11 of the top- and backsheets6, 7 define between the front and rear sections 10, 11 a crotch area 12having opposite side edges formed with identical notched edges 13, 14,respectively, so as to define the respective leg-openings 2. Thebacksheet 7 may include water-impermeable plastic film (not shown) beingstretchable both in length and width and bonded to the inner side of thebacksheet 7 with adhesive intermittently applied thereto. Sucharrangement will perfectly prevent excretions from passing through thebacksheet 7. Where the film is bonded at least along its outerperipheral area to the topsheet 6 with intermittently placed spots ofadhesive, the top- and backsheets 6, 7 as components of the diaper Iwill be improved not only in elasticity but also in tensile stress andthereby the fitness characteristic of the diaper 1 on the wearer's bodywill be further improved.

The elastic means 4 associated with the leg-openings comprises aplurality of first elastic members 4A and a plurality of second elasticmembers 4B. The first and second elastic members 4A, 4B extend inparallel to each other along their intermediate lengths 4A₂, 4B₂ andintersect each other substantially at middle points along the respectivenotched edges 13, 14, then extensions 4A₁, 4B₁ diverge from therespective intersections 4C so as to extend along the respective notchededges 13, 14. The divergent extensions 4A₁, 4B₁ are bonded to the innersurface(s) of the back- and/or topsheet(s) with adhesive 17 but theintermediate parallel lengths 4A₂, 4B₂ are positioned in substantiallyin a central area of the core across the crotch area 12 without beingbonded to any of the back- and topsheets.

The first and second elastic members 4A, 4B are so arranged that therespective divergent extensions 4A₁, 4B₁ have the tensile stressgradually decreasing from their longitudinally inner ends (saidrespective intersections) 4C corresponding to the bottoms of therespective leg-openings toward their longitudinally outer ends 4Dcorresponding to the tops of the respective leg-openings, i.e.,gradually increasing from their longitudinally outer ends 4D towardtheir longitudinally inner ends 4C.

In addition, a plurality of the first elastic members 4A and a pluralityof the second elastic members 4B are so arranged to have theirinter-member spacings along the respective divergent extensions 4A₁, 4B₁gradually enlarged from their longitudinally inner ends 4C (saidrespective intersections) toward their longitudinally outer ends 4D,i.e., gradually reduced from their longitudinally outer ends 4D towardtheir longitudinally inner ends 4C (said respective intersections).

FIG. 3 is a plan view illustrating by way of example the manner in whichthe first and second elastic members 4A, 4B are arranged as has beendescribed above. Adhesive is applied onto the backsheet 7 at givenintervals longitudinally thereof so as to surround successive ellipsesand thereby to define adhesive areas 17' while the backsheet 7 is movedlongitudinally thereof at a given velocity. Simultaneously, a pluralityof the first continuous elastic members 4A and a plurality of the secondcontinuous elastic members 4B, both being stretched at a givenelongation percentage, are inserted into the corresponding number offirst and second traverses (not shown) which are, in turn, activated sothat the first and second elastic members 4A, 4B are bonded to thebacksheet 7 along the adhesive areas 17', describing curvessubstantially corresponding to sine curves. These curves are symmetricwith respect to a longitudinally centre line of the backsheet 7. Thefirst and second elastic members 4A, 4B travel from a starting point P₁to a turning point P₂, then from the turning point P₂ to the newstarting point P₁, respectively, by a width W for each cycle. Theirelongation percentage increases during travel from the starting point P₁to the turning point P₂ and consequently their tensile stress alsoincreases, since the first and second elastic members 4A, 4B understretching with a given elongation percentage having been linearlytraveling longitudinally of the backsheet 7 are forcibly deflected bysaid traverses transversely of the backsheet 7, resisting against suchdeflection, and, as a consequence, the first and second elastic members4A, 4B are stretched in the course of traveling from the starting pointP₁ to the turning point P₂, respectively. It will be understood thatsaid elongation percentage depends upon the velocity at which the firstand second elastic members 4A, 4B are fed longitudinally of thebacksheet 7 as well as the velocity at which said traverses movetransversely of the backsheet 7. Meanwhile, spacings of componentelastic members in each plurality of elastic members 4A, 4B are reducedas each plurality of elastic members 4A, 4B having been linearlytraveling longitudinally of the backsheet 7 is forcibly deflected by theassociated traverse transversely of the backsheet 7 from the startingpoint P₁ to the turning point P₂. It will be understood here again thata degree of such inter-member spacing reduction depends upon thevelocity at which the first and second elastic members 4A, 4B as well asthe backsheet 7 travel.

The lengths (the intermediate parallel length 4A₂, 4B₂ in FIG. 2) of thefirst and second elastic members 4A, 4B extending between each pair ofintersections 4C and being closely adjacent to each other are loosenedto be brought further close together since the area of the backsheet 7corresponding to these intermediate parallel lengths 4A₂, 4B₂ carries noadhesive. However, these intermediate parallel lengths also may bebonded to the backsheet 7 with adhesive, if desired, by applyingadhesive onto said area of the backsheet 7 or the first and secondelastic members 4A, 4B may be entirely coated with adhesive. In thelatter case, obviously no adhesive will be applied onto the backsheet 7at all.

The elastic means 5 surrounding the waist-opening is bonded to innersurface(s) of the top- and/or backsheet(s) with adhesive along a waistline 16.

Though not shown, the core 8 is bonded, on its top side and/or bottomside, to the topsheet 6 and/or the backsheet 7 with spots of adhesiveintermittently placed thereon. A laminar structure formed in this mannermay be folded in two along its longitudinally centre line and thenopposite free edges thereof may be joined together by means of heat sealto provide the individual diaper I as shown by FIG. 1.

Such diaper I may be obtained by employing the method for makingdisposable briefs as disclosed in Japanese Patent Application No.1989-167224 filed in the name of the same applicant as of the presentapplication. However, it should be understood that the present inventionis not limited to the form of pants or briefs. Specifically, it ispossible within the scope of the invention that, instead of folding saidlaminar structure along its longitudinally centre line in two followedby Joining the opposite free edges together by means of heat seal, therear section 11 of said laminar structure is provided at opposite sideswith suitable fastener means such as strips of pressure tape by whichthe waist line 16 of the laminar structure (garments) is fixedlycompleted as in the case of so-called open type diaper. It is alsopossible even to omit the core 8, depending upon the type of garments.

The topsheet 6 and the backsheet 7 may be of water-permeable nonwovenfabric being stretchable both in length and width, the core 8 may be offluffy pulp mixed with hightly water-absorbent polymer particles, andthe elastic members may be of natural or synthetic rubber or the like.

What is claimed is:
 1. A disposable garment in assembled conditionhavinga topsheet and a backsheet disposed in an overlying relationshipspaced apart first and second leg openings, each leg opening having anupper end portion and a lower end portion a crotch area extendingbetween said lower end portions of said leg openings means forelastically surrounding each of said leg openings, the improvementcomprising said means for elastically surrounding each of said legopenings comprising a plurality of first elastic members and a pluralityof second elastic members, said first elastic members extending alongone-half of said first leg opening, across said crotch area and thenalong one half of said second leg opening, said second elastic membersextending along the other half of said first leg opening, across saidcrotch area and then along the other half of said second leg opening,said first and second elastic members intersecting each other adjacentsaid lower end portion of each leg opening, the tensile strength of saidfirst and second elastic members gradually decreasing from a locationadjacent said lower end portion of each leg opening to said upper endportion of each leg opening.
 2. A disposable garment in assembledcondition havinga topsheet and a backsheet disposed in an overlyingrelationship spaced apart first and second leg openings, each legopening having an upper end portion and a lower end portion a crotcharea extending between said lower end portions of said leg openingsmeans for elastically surrounding each of said leg openings,theimprovement comprising said means for elastically surrounding each ofsaid leg openings comprising a plurality of first elastic members and aplurality of second elastic members said first elastic members extendingalong one-half of said first leg opening, across said crotch area andthen along one half of said second leg opening, said second elasticmembers extending along the other half of said first leg opening, acrosssaid crotch area and then along the other half of said second legopening, said first and second elastic members intersecting each otheradjacent said lower end portion of each leg opening, the lateral spacingbetween each of said first elastic members gradually increasing from alocation adjacent said lower end portion of each leg opening to saidupper end portion of each leg opening and the lateral spacing betweeneach of said second elastic members gradually increasing from a locationadjacent said lower end portion of each leg opening to said upper endportion of each leg opening.
 3. A disposable garment in assembledcondition according to claim 2 wherein the tensile strength of saidfirst and second elastic members gradually decreases from a locationadjacent said lower end portion of each leg opening to said upper endportion of each leg opening.